Plaster and process of controlling the setting of plaster, an accelerator therefor, and process of making such accelekator



. slow in setting when mixed with water.

Patent .lluly 1923.

11*, T i: i

JOSEPH N. WIGGIN, OF EAST ORANGE, NEW JERSEY, ASSIGNOB T0 H. B. WIGGINS SGNB COMPANY, OF BLOOMFIELD, NEW

JPLASTJER AND PROCESS OF ERATGR THEREFOR,

We Drawing.

To all whom it may concern: 'Be it known that I, JosEPH N. WIGGIN, a citizen of the United States, residing at East Oran e, in the county of Essex and State of ew Jersey, have invented a certain new and useful Improvement in a Plaster and Processes of Controlling the Setting of Plaster, an Accelerator Therefor, and l rocesses of Making such Accelerator of which the following is a specification. he object of my invention as been to provide -a plaster and a process of controlling the setting of plaster, an accelerator for plasterand a process of making such accelerator, whereby uniformityand definiteness of time of setting can be obtained; whereby the time of the setting of plaster, and articularly plaster of Paris, may be control ed; whereby crystallization throughout the mass shall be uniform; Wherebygreater cohesion and strength may be obtained than ordinarily; and whereby such results can beobta-ined economically, and to such ends my invention consists in a plaster and a process of controlling the setting of plaster, an accelerator therefor and a process of making such accelerator hereinafter specified.

My invention relates to plaster and par ticularly plaster of Paris, and l shall illustrate it by its application to plaster of Paris intended for dentists, but the illustrated embodiment is only to be regarded as typical of many possible embodiments, and my invention is not to be confined thereto.

For dental Work, it is desirable that a powdered laster be furnished, such that the time which it requires for the plaster to set can be controlled in advance, so that the setting will take place within, say, a given number of minutes. It'is also desirable that such plaster shall have great cohesion and strength; that it may be made without the use 0 foreign substances; that the crystallization shall be uniform throughout the mass; and that it shall be economical.

My plaster has been proven by extensive eriments to possess these qualities. ure plaster of Paris is comparatively provide an accelerator to hasten the setting. it desire to be able to sell a mixture, in

powdered form, of the plaster of Pari with plaster of ring it all the time,

JERSEY, A CORlORA'I'ION OF NEW JERSEY.

CONTROLLING THE SETTING OF PLASTER, AN ACCEL- AND PROCESS OF MAKING SUCH ACCELERATOR.

Application filed April 29,1a2o. Serial no. 377,707.

the accelerator, which mixture shall remain in powdered form until it is desired to use it.

I have found that powdered plaster of Paris having a definite amount of water in a definite amount of plaster acts very favorably as an accelerator, and that where the amount of water in such accelerator is less than is necessary to olidify the entire mass, it will remain in powdered form whenproperly treated and can be mixed with the pure Paris without causing the latter to solidify.

I have found that by varying the proportion of water in the accelerator and by varying the proportion of accelerator in the mass of pure plaster of Paris, I can control the time of setting.

So far as known to me no one before me ever used as an accelerator plaster of Paris in which less water is present than is necessary to solidify the wholemass.

A further advantage of using an accelorator, in which the proportion of water is less than that necessary to solidify the whole mass, or to produce complete crystallization throughout'the mass, is that a larger mass of accelerator is used than would be the case if the full amount of water necessary for such solidification were present, and this larger mass is more easily distributed uniformly throughout the mass of pure laster of Paris than would be the case i the mass of accelerator were smaller. This more uniform distribution of the accelerator results in more uniform crystallization taking place when" setting does occur. This more uniform crystallization gives reater cohesion and strength and it also gives that uniformity of time of setting which enables me to sell a mixture which will, with certainty, set in a definite desired time.

In preparing my accelerator, I preferably place a definite amount of powdered plaster of Parisin a mixing machine and sprinkle in a certain amount of water, stirsay, for one hour; then draw off the mixture of plaster and I water and let it stand for a considerable and finally pulverize ittime, say, one day, to a unlform size, for instance, Wlll pass through a 200-mesh sieve.

a size that As an example of the proportion of water to plaster in my accelerator, one ounce of water may be used to one pound of plaster, by weight. In this proportion the accelerator is quite stable. By increasing the proportion of water the accelerator will Work more rapidly.

My process of forming the accelerator solves the problem of getting a definite amount of water in a definite amount of plaster and still. keeping it in powdered form. While I have'given the reasons and elfects involved in my invention, as I suppose them to be, I do not vouch for them as being correct, nor as being the onl reasons or efl'ects which are involved. xtensive experimentation has shown that my accelerator and plaster very effectually accomIplish the objects in view.

Ivy mixture of plaster and accelerator can not only be used without other substances, but desirable mixtures with other substances can be made. For instance, cement may be added in varying proportions, say, two parts of plaster to one part of cement.v Or magnesium oxide or magnesium chloride or a mixture ofjboth may be added to my mixture of plaster of Paris and accelerator. Many other mixtures are possible.

Throughout the claims by the terms water? and water of crystallization, etc., is meant water which causes the plaster to set as distinguished from water which necessarily enters into the molecule of plaster to constitute the latter before setting.

I claim:

1. A plaster of Paris composition comprising a mass of powdered plaster of Paris substantially without water and a second mass of plaster of Paris having water mixed therewith, but in less proportion than would be suflicient to solidify said second mass.

'2. A plaster of Paris composition comprising powdered plaster of Paris substantially without Water of crystallization, a

powdered plaster of Paris having water therein of an amount less than sufficient to solidify said latter powdered plaster of Paris.

3. A process of controlling the setting of plaster consisting inmixing therewith a mass of plaster having fluid of crystallization but of less amount than sufiicient to solidify said mass, and proportioning said mass of plaster to the body of plaster, whose setting is to be controlled, according to the time of setting desired.

4. A process of controlling the setting of plaster of Paris consisting in mixing therewith a mass of plaster of Paris having menses water therein but of less amount than sulficient to solidfy said mass.

5. A process of controlling the setting of plaster of Paris consisting in mixing therewith a definite amount of accelerator, which accelerator consists of plaster of Paris having water therein but of less amount than suflicient to solidify the mass of said accelerator.

6. A process of making an accelerator for a settable plaster consisting in mixing water with a mass of set-table plaster to an amount less than suflicient to set said mass of plaster.

7 A process of making an accelerator for plaster of Paris consisting in mixing with a mass of plaster of Paris an amount of Water less than suflicient to solidify said mass.

8. A process of making an accelerator for plaster of Paris consisting in mixing with a mass of powdered plaster of Paris a proportion of water less than the amount suflicient to solidify said mass and afterwards pulverizing said mass. l 9. A process of making an accelerator for plaster of Paris consisting in mixing with a mass "of powdered. plaster of Paris a definite amount of water less than the amount sufficient to solidify said mass and afterwards pulverizing said mass.

10. A process of making an accelerator for plaster of Paris consisting in mixing water with a mass of powdered plaster of Paris, said Water being in less proportion than sufficient to solidify said mass, permitting said mixture to stand until said water has been taken up and then pulverizing the mass.

11. A process of making an accelerator for plaster of Paris consisting in mixing water with a mass of powdered plaster of Paris, said water being in less proportion than sufiicient to set the said mass and agitating said mass while mixing the water therewith.

12. A process of making an accelerator for plaster of Paris consisting in sprinkling into a mass of plaster of Paris an amount of. water less than sufiicient to set said mass of plaster.

13. A process of making an accelerator for plaster of Paris consisting in sprinkling into a mass of plaster of Paris an amount of water less than sufficient to set said mass of plaster and agitating said mass while sprinkling and mixing said water therewith.

In testimony that I claim the foregoing, I have hereunto set my hand this 27th day of April, 1920.

JOSEPH N. VVIGGIN. 

